1. Field of the Invention
This invention relates to an improved thermally actuatable electrical switch construction and to a sub-assembly therefor as well as methods and apparatus of making the same.
2. Prior Art Statement
It is known to provide a thermally actuatable electrical switch construction having a housing means carrying an electrically insulating end plug provided with an opening passing therethrough and in which a portion of a conductive lead is disposed so that opposed ends of the lead extend beyond opposed ends of the end plug and respectively define a fixed contact means inside the housing means and a terminal means outside the housing means. The lead has means interlocking with the end plug to prevent axial movement of the lead into the housing means. The means of the lead interlocking with the end plug comprises an integral part of the terminal means extending outboard of the opening and disposed against the respective opposed end of the end plug that is adjacent the terminal means whereby the lead and the part thereof comprise a one-piece member.
For example see FIGS. 8 and 9 of the U.S. Pat. No. 3,180,958 to Merrill, wherein the lead 118 is crimped at 119 and FIGS. 3, 4 and 5 of the Japanese Pat. No. 54-5743 wherein in FIG. 3 it appears that the lead 2 is crimped at 13, in FIG. 4 it appears that the lead 2 is split at 14 to provide abutments 15, and in FIG. 5 it appears that the lead 2 is lanced at 16 to provide opposed tabs 17.
Another prior known means for interlocking the lead to the end plug forms the portion of the lead that is disposed in the opening of the end plug with a plurality of radially disposed reliefs in a manner to prevent each relief from extending around the circumference of the lead so as to cause the sealing compound means to enter the reliefs and form set blocks of subsequently hardened sealing means that tend to prevent axial movement of the lead into the housing means as well as to tend to prevent rotational movement of the lead relative to the end plug. For example, see U.S. Pat. No. 4,060,787 to Budnik.